1. Field of the Invention
This invention generally relates to shutter apparatuses for use in optical apparatuses, and more particularly, to a shutter apparatus suitable for use in an optical apparatus such as a digital camera, camcorder, or the like.
2. Description of the Related Art
In recent years, as a shutter apparatus incorporated into a digital camera or the like has been downsized, a shutter speed has been increased. For instance, Japanese Patent Application Publication No. 2002-162666 (hereinafter, referred to as Patent Document 1) discloses the shutter apparatus of this type. The shutter apparatus disclosed in Patent Document 1 includes two shutter blades that open and close by the swing of an opening portion for exposure. The shatter blades respectively have connecting openings, into which a driving pin that reciprocates is inserted. As the driving pin moves, the shutter blade operates to open and close the opening portion. In the above-described connecting opening, there are provided a closing-side inner margin and an opening-side inner margin, whereas the driving pin is engaged in the closing-side inner margin at a closing operation and engaged in the opening-side inner margin at an opening operation. Also, in the closing-side inner margin, there is formed a backward inner margin that moves backward in an opposite direction from a closing direction.
It is configured in such a manner that the shutter opening can be closed at high speed by providing the backward inner margin as described above. Also, an allowance space W is arranged between the above-described closing-side inner margin and the opening-side inner margin so that the driving pin can move freely. The allowance width W decreases the load at the beginning of the movement of the driving pin, and the shutter blades perform a closing operation after the driving pin is sufficiently accelerated. In the shutter apparatus described in Patent Document 1 as stated, the shutter speed is increased and the shutter apparatus is downsized by providing the backward inner margin and the allowance width W.
The shutter apparatus disclosed in Patent Document 1, however, has a spindle of each sector serving as a center of swing is located in a place that does not interfere with the other sector. That is to say, each sector spindle is provided not to overlap a stopping place or a passing place of the other sector. FIG. 8 is an enlarged side view of a spindle (also known as Dübel) of a first sector 105 and periphery thereof in a commonly used shutter apparatus 100. A spindle 103 is integrally formed with a substrate 101 in a state of extruding from the substrate surface. A head side of the spindle 103 is inserted into a hole 107 provided in a supporting plate 102. The spindle 103 is fixed on a given position in the afore-described configuration. The first sector 105 is configured to swing around the spindle 103.
In order to downsize the shutter apparatus 100, it is preferable that the spindle 103 be arranged in a place of an arrow SP shown in FIG. 8. However, a second sector 106 swindles in this place, and thereby, it is impossible to locate the spindle 103. Accordingly, as shown in FIG. 8, the spindle 103 of the first sector 105 is conventionally provided in a place that avoids a region of interfering with the second sector 106. Here, only the spindle 103 of the first sector 105 is shown in FIG. 8, yet the spindle of the second sector 106 is also arranged in a place that avoids interfering with the first sector 105.
As described, in a conventional shutter apparatus, the spindle of one sector is arranged not to interfere with that of the other sector. Consequently, there is a problem in the conventional shutter apparatus in that a sector location is limited in order to avoid interfering with the other sector, even if there is a place where the spindle would like to be located in view of downsizing the shutter apparatus and assembling efficiency thereof.